David W. answered • 06/16/15
Tutor
4.7
(90)
Experienced Prof
A cross section of a pyramid gets smaller and smaller as you move toward the top point. If the plane making the cross section is parallel to the base, each cross section will look like the base, only smaller. So, if you have a triangular pyramid, it will be a triangle.
This shows a rectangular pyramid, but look closely at the back of a U.S. $1 bill.
David W.
O.K., I googled (actually, Binged) to find:
A rectangular pyramid is built on a rectangular base, with two sets of triangles forming the sides.
(note: the dollar bill has a square)
In geometry, a pyramid is a polyhedron formed by connecting a polygonal base and a point, called the apex. Each base edge and apex form a triangle, called a lateral face.
In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons) is a polyhedron composed of four triangular faces, three of which meet at each corner or vertex.
So, a rectangular pyramid isn't called a tetrahedron, a triangular pyramid is, right? PLZ comment, it has been a lot of years since I studied this.
Report
06/16/15
Casey W.
A rectangular pyramid is (the top or bottom) half of an octahedron...which itself is the dual of a cube!
06/16/15